The disclosure relates to an internal gear pump having the features of the disclosure. Such internal gear pumps are used, for example, instead of the piston pumps normally used in wheel slip-controlled and/or power vehicle brake systems and are often also referred to as return pumps.
Internal gear pumps are known. They comprise a pinion, that is to say an externally toothed gear wheel, which is arranged eccentrically in an internally toothed ring gear and at a point on the circumference or in a portion of the circumference meshes with the ring gear. The pinion and the ring gear may also be thought of as gear wheels of the internal gear pump. Through rotational driving of one of the two gear wheels, usually the pinion, the other gear wheel, that is to say usually the ring gear, is also driven to rotate and the internal gear pump delivers fluid in a manner known in the art; in a vehicle hydraulic brake system it delivers brake fluid.
Opposite the portion of the circumference in which the pinion meshes with the ring gear, the internal gear pump comprises a crescent-shaped clearance space between the pinion and the ring gear, which is referred to here as the pump chamber. A separator, which divides the pump chamber into a suction chamber and a delivery chamber, is arranged in the pump chamber. Owing to its typical shape the separator is also referred to as the crescent or crescent piece, another term being the filling piece. A typically hollow cylindrical inner side of the separator bears against tooth tips of teeth of the pinion and a typically outwardly curved outer side of the separator bears on tooth tips of teeth of the ring gear, so that the separator encloses volumes of fluid in tooth spaces between the teeth of the gear wheels of the internal gear pump. Rotational driving causes the gear wheels to deliver the fluid in the tooth spaces from the suction chamber into the delivery chamber.
The published patent application DE 10 2007 050 820 A1 discloses such an internal gear pump having a crescent-shaped, one-piece separator, which is pivotally supported at its circumferential or longitudinal center. Directional specifications such as “circumference” or “radial” relate to the internal gear pump. In the event of play between the separator and the tooth tips of the gear wheels the separator can pivot, so that at one end it bears on the tooth tips of the teeth of the pinion and at the opposite end on tooth tips of the teeth of the ring gear. A pressure in tooth spaces of the pinion and the ring gear prevailing when the internal gear pump is in operation produces a torque on the separator, which has a pivoting action and maintains the bearing contact of the one end of the separator against the tooth tips of the teeth of the pinion and of the opposite end of the separator against the tooth tips of the teeth of the ring gear.